Spacers for bundled overhead line conductors



J. E. COX ETAL Nov. 19, 1-963 SPACERS FOR BUNDLED OVERHEAD LINE CONDUCTORS 4 Sheets-Sheet 1 Filed Feb. 14, 1962 &

Inventor 0:5.

By BMW M Attorney Nov. 19, 1963 J. E. cox ETAL 3,111,552,

SPACERS'FOR BUNDLED OVERHEAD LINE CONDUCTORS Filed Feb. 14, 1962 4 Sheets-Sheet 2 Nov. 19, 1963 J. E. cox ETAL SPACERS FOR BUNDLED OVERHEAD LINE CONDUCTORS 4 Sheets-Sheet 3 Filed Feb. 14, 1962 lnvenlor y W M7 (tow Nov. 19, 1963 .1. E. cox ETAL SPACERS FOR BUNDLED OVERHEAD LINE CONDUCTORS Filed Feb. 14, 1962 4 Sheets-Sheet 4 I nvenlor United States Patent F 3,111,552 SPACERS FGR BUNDLED OVERHEAD LINE CQNDUCTORS John Edward Cox, 5 Marian Ciose, Rainhill, near Liverpool, Engiand, and William Gibbon, S Paignton Road, Liverpool 16, England Filed Feb. 14, 1962, Ser. No. 173,191 Claims priority, application Great Britain Feb. 20, 1961 Claims. (Cl. 174-40) This invention relates to spacers for bundled conductors of overhead electric power lines. Such bundled conductors comprise two or more parallel interconnected but separate conductors, usually stranded conductors, held in spaced relationship to one another through-out the span by one or more spacers each comprising at least two interconnected clamps for attachment to conductors of the bundle. The function of the spacers is to hold the individual conductors of the bundle apart while allowing a certain freedom of movement of the conductors with respect to each other, especially relative longitudinal movement.

The spacer in accordance with the invention comprises at least two clamps, for attachment to two conductors of the bundle, spaced apart by a tubular strut and tied together by a tie member located within the tubular strut. When, as is preferred, the tie is a flexible metal strip, each end of the strip is secured to one of the clamps in such a way that it will lie in a plane substantially at right angles to the axis of the conductor to which the clamp is attached. The strut is preferably a flexible tube, but when it is not it is pivotally coupled at its ends to the clamps to permit movement between each end of the tube and the adjacent clamp substantially in the common plane of the conductors and pref" erably in such a way as to resist relative movement other than in this plane.

The tubular strut may be of a rubber or rubber-like material but it preferably consists of a close coiled helical spring constructed to withstand the compressive forces to which it is subjected in use. The diameter of the spring will normally be uniform but it may vary, for example a barrel shaped spring may be used. Such a tubular strut can be rigidly attached at its ends to the clamps, for example by fitting it over a spigot projecting from the clamp in such a way that its end butts against a shoulder at the root of the spigot or by fitting the end or the strut into a blind hole in the clamp and contracting the surrounding Walls on to it by compression.

When a tie in the form of a metal strip is rigidly attached at its ends to the clamps, the strip is preferably transversely corrugated to allow for the slight extension necessary when the tube is flexed. The depth of the corrugations is kept to a minimum so that the susceptibility of the spacer to flexing in the plane at right angles to the common plane of the conductor is not materially increased. We prefer however not to attach the tie member rigidly to the clamps but to extend the effective part of the tie member between two supporting structures each comprising a rigid .member attached to the tie member and a flexible member attached to the clamp or arranged between the rigid member and an abutment, fixed with respect to the clamp, which may be and preferably is the part of the strut that is attached to the clamp. The nature and location of the flexible members must be such that although they transmit suflicient tensile stress from the clamps to the tie member to prevent undue extension of the spacer they can be distorted either under compression or tension to an extent to permit bending of the spacer to the requiredextent without extension of the tie member.

3 1 1 1,55 2 Patented Nov. 19, 1963 When the tubular strut consists of a close coiled helical spring, such flexible members may each consist of an extension of the spring, in which the turns are spaced.

apart sufliciently to provide the necessary flexibility under compression. In this case the parts of the spring immediately adjacent the extensions are rigidly attached to the clamps and in eifeot form fixed abutments for the open coiled extensions of the spring. This attachment can conveniently be effected by fitting the spring into a cylindrical bore in the clamp and making a compression joint between the clamp and the spring, where it passes into the bore.

Alternatively, the flexible members may consist of separate springs or pads of elastomeric material each arranged between a rigid member attached to the tie and an abutment on the clamp and may either be permanently attached to the abutments or provided with a form of interlocking connection with the abutments that prevents relative transverse movement between the flexible members and the tube. For example, when a metal spring is used it can be welded to the end of the tube and when a rubber pad is used it can either be bonded to the end of the tube or formed with a spigot which fits into the end of the tube.

The rigid members to which the ends of the ties are attached can conveniently be in the form of metal discs of approximately the same outside diameter as the tube. Such discs may either be permanently attached to the flexible member, as by welding or pinning when the flexible member is a metallic: spring or by bonding when the flexible member is an elastomeric pad, or detachably fitted on to the flexible member, as by a spigot and socket connection. For example, a spigot on the disc can fit into the spring or a spigot on the elastomeric pad can fit into a recess in the disc.

When permanent connections are made between each flexible member and both the tube and the respective rigid member, relative rotation about the axis of the spacer between the tie and the clamps is inhibited, but when there is no such permanent attachment and the nature of the interlocking between these various members is such that relative rotation may take place other precautions are necessary. We prefer to prevent such relative rotation by making the rigid members or parts associated therewith of such a shape relative to the parts of the clamps within which they are located that relative rotation between the rigid members and the clamps cannot take place. For example, the rigid members may fit loosely into hexagonal or other non-circular bores in the clamp and may themselves be of a corre sponding shape, the relative dimensions being such that although the disc has suflicient freedom of movement to enable the necessary flexing of the tube to take place, relative rotation between the discs and the clamps is prevented. Alternatively, the ends of the tie member can project through the rigid members into slots in the bodies of the clamps in such a way that although some movement between the tie members and the clamp bodies is allowed, undue relative rotation between these two members on the axis of the clamp is prevented.

Although it has been implied above that the structures consisting of the flexible and rigid members are located in bores in the clamp bodies, this is not essential. For example each end of the tube may be gripped by a ring shaped part of the clamp attached to the main body of the clamp by spiders between which the structure consisting of the rigid and flexible members is located. This alternative arrangement has the advantages that, during the assembly of the spacer, the flexible and rigid members can be visually located within the clamp and that water and other contaminating elements are prevented from collecting within the part of the clamp in which the rigid and flexible members move. When the assembly is located in a blind bore in the clamp body it is advisable to pack the space between the bore and the assembly with grease.

In making the preferred form of spacer in accordance with the present invention, the flexible tube and tie member can be built up as a sub-assembly, with the tie supported within the tube by means of rigid end members and flexible members between the rigid members and the ends of the tube, and this whole sub-assembly can then be fitted and secured to the clamps by compression jointing a ring shaped part of each clamp on to the tube at or near its ends.

A number of spacers in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is an elevation, partly in section, of one form of spacer,

FIGURE 2 is a plan, partly in section, of part of the spacer shown in FIGURE 1,

FIGURES 3 and 4 are a plan and elevation respectively, partly in section, of one end of another form of spacer,

FIGURES 5, 6, 7 and 8 are sectional elevations of parts of four further forms of spacer, and

FIGURES 9 and 10 are diagrammatic drawings of spacers for three and four conductors respectively.

Referring to FIGURES 1 and 2 the first spacer comprises two identical 2-part cast metal clamps 1 and 2 for attachment to the conductors, spaced apart by a strut in the form of a flexible steel tube 3 and tied together by a flexible steel strip 4. The spacer is shown attached to a pair of parallel conductors 5 and 6 lying in the same horizontal plane. Each clamp comprises two parts, hinged together by a pin 7 lying parallel to the conductor at the outside end of the clamp, a main part 8 which forms the body of the clamp and a second part 9 which can be drawn towards the main body of the clamp, to grip the conductor 5 or 6, by means of a screw (not visible) which passes through the part 9, vertically upwards into a threaded bore in the body 8 of the clamp. The clamps are so designed that their outer surfaces are substantially free from ridges and projections.

The inner end of the body of each clamp (as at 10, FIGURE 1) is initially substantially cylindrical and is formed with a large diameter blind hole, with its axis at right angles to the conductor axis, which forms a socket for the flexible tube 3. Within this socket is a narrow vertical diametric slot to receive the end 11 of the flexible steel strip 4. The tube 3 is made from a corrosion resistant material such as stainless steel wire of circular cross section close coiled with the turns butting to form the tube wall. The ends of this tube fit into the sockets in the clamps 1 and 2 and are secured by compressing the wall of the socket on to the end of the tube 3 by means of dies which shape this part of the clamp as a hexagon (as at 12). To give added security, before compression is applied the end turns of the coil are separated by a short distance to provide a slot 13 into which the metal of the clamp body flows during compression.

During the compression of the clamp body on to the tube, the flexible steel strip 4 is also gripped in the slots provided therefor. At its ends the edges of the steel strip are castellated over a short distance as at 14 so that, during the compression of the clamp body on to the tube and strip, metal flows between the castellations and thus firmly anchors the strip in the clamp body. The width of the strip is slightly less than the internal diameter of the tube and the strip is transversely corrugated (see FIGURE 2). When the spacer is in use, the strip lies in a vertical plane, that is, in a plane at right angles to the common plane of the two conductors to which the clamps are attached.

When flexing of the tube is caused by relatively longitudinal movement between the conductors, the corrugations in the strip allow for the necessary extension of the strip. The spacer resists vertical movement of either conductor with respect to the other, since this would involve flexing of the strip in its own plane, but allows relative twisting of the two clamps about the axis of the tube.

In a modified form of this spacer (not shown) the inner ends of the clamp bodies are formed with spigots over which the ends of the tube fit. The steel strip is secured in the same way by compression and the ends of the tube can be secured on the spigots by any suitable form of clamping ring. At the root of each spigot is a shoulder against which the end of the tube bears.

In the spacer of which one end is shown in FIGURES 3 and 4, similar clamps to those described above are used but the inner end of each clamp, which is of generally cylindrical shape, is formed with a nose 20 having a central cylindrical bearing surface, the axis of which is vertical. The strut is a rigid aluminium tube 21 into each end of which fits a nylon plug 22 having at its outer end a concave cylindrical surface 23 which bears against the convex cylindrical surface of the nose 22. That mating surfaces of the nose and plug are such that, when the tube 21 moves with respect to the clamp 24 in the plane of the conductors, there is a combined rocking and sliding action between these surfaces. The tube 21 can pivot relatively to the clamp 24 through an angle of about 30.

The tie is a stainless steel strip 25 secured at 26 in a vertical slot in the clamp body by compression but in this case the part 27 of the slot passing through the nose 22 of the clamp body is V-sh-aped to allow for the desired amount of flexing of the strip 25 with respect to the clamp body. The strip 25 passes through a V-shaped slot 28 in the nylon plug 22 at the end of the tube 21. In this case it is unnecessary to corrugate the steel strip 25 to allow for its extension during the movement in the common plane of the conductors of the tube 21 with respect to one or both clamps (24).

The joint between the end of the tube 25 and the clamp 24- is protected by a neoprene sleeve 29 which fits on to the end of the tube 25 and over an integral flange 30 formed on the inner ends of the clamp body.

To give the spacer the necessary compression strength, the nylon plugs (22) are made of the same diameter as the outer diameter of the tube 21 and are formed with spigots which fit tightly into the ends of the tube so that the ends of the tube bear against shoulders at the roots of the spigots. The two ends of the spacer are identical.

In this form of spacer the angle through which the tube can move with respect to each clamp is positively limited in that when the maximum angle is reached, further movement is prevented by contact between the steel strip and the inner surfaces of the V-shaped slots in the nose of the clamp body and the nylon plug and by contact between one side of the nose and one side of the concave groove in the nylon plug.

As before, movement of one conductor vertically with respect to the other is restrained, since such movement involves flexing of the strip in its plane, but relative twisting between the clamps about the axis of the tube can take place.

In another form of spacer, part of which is shown in FIGURE 5, the strut is the middle part of a helical steel Wire spring 49 close coiled along the whole of its length except for short lengths of a few turns at each end (as at 4d), where the turns are spaced apart by a short distance, the close coiled part acting as the strut. The end of the spring 41} fits into an axial blind bore in the body of the clamp 42, the bore being of greater diameter than the outside diameter of the spring. Except for the dimensions of the bore, the clamp is similar to that described with reference to FIGURE 1. The tie member, in the form of a flat steel strip 43', passes axially through the centre of the spring 4i) and is held in position by a pair of steel discs (such as 44), one welded to each end of the spring 44). The ends of the strip 43 fit through slots in these discs and are secured in the discs by pins such as 4 5 in such a way that a short length of the strip 46 projects from the opposite sides of the discs to those welded to the end of the spring 40. Alternatively the strip 43 can be welded to the discs. The two ends of the spacer are identical.

When an end of the spring assembly is fitted into the bore of the clamp, this projecting end of the tie member fits loosely into a slot in the flat end of the bore. The spring is secured in the bore by compressing the open end of the bore on to the spring as at 47, the part of the spring gripped in this way being the extreme end of the closely spaced part of the spring. The length of the part of the spring with open turns is such that the disc 44 to which the tie member 43 is secured is spaced a short distance from the end of the blind here. The only function of the slot in the clamp body 43 is to ensure that before the compression joint is made the relative location between the tie member 43 and the clamp body is correct. Relative rotation between the tie member and the clamp body is prevented by the fact that the disc 44 is secured to the end of the spring dil in such a way that relative rotation between them cannot occur.

FIGURE 6 shows a modification of the spacer of FIG- URE 5 in which the flexible member instead of being formed by an extension of the tubular spring (as at 41, FIGURE 5) is a separate pad Ell of elastomeric material; the only other modification is that the tubular spring 51 terminates at the end of the part with closely spaced turns to enable the open spaced parts thus omitted to be replaced by the pad 50 which bears against and is secured to the end of the spring 51. Alternatively the pad could be secured to a step in the bore of the clamp 42', adjacent the ends of the spring 51.

In another modified form of spacer shown in FIGURE 7, the tie member 55' is secured at each end to a steel disc 56 Welded to the end of a short length of close coiled spring 57. The short length of spring 57 is secured into 'ie clamp body =53 by a compression joint at 59. The strength of the spring 57 is such as to provide sufiicient resistance to relative rotation between the tie member 55 and the clamp body 58 about the axis of the spacer.

FIGURE 8 shows a modified form of the spacer shown in FIGURE 5 in which, instead of using an extension of the strut spring as the flexible member, a separate spring 66' is used and this spring 6% is arranged between a steel disc 61 attached to the end of the tie member 62 and a metal plate 63 which bears against the end of the close coiled spring 64 forming the tubular strut. Relative rotation between the tie member 62 and the clamp body 65 can be prevented either by attaching the disc 63 both to the clamp body and to the spring as or by making the bore 66 in the clamp 65 of non-circnlar cross section and correspondingly shaping the disc 61.

The spacers described with reference to FIGURES 5 to 8 have the advantages over those described with reference to FEGURES 1 and 2 that the tension member does not need to be extendable and need not therefore be corrugated. The need to find a balance between the elasticity, tensile strength, fatigue life and the thickness of the tension member is eliminated and hence it can be made of thicker material of standard dimensions and commercial strength.

All of the spacers particularly described by way of example are designed for. attachment to two conductors only. When there are more than two conductors in the brindle a number of such spacers can be used at each location where spacing is to be affected or alternatively the spacers can be modified to make them suitable for attachment to more than two conductors, for example as shown in FIGURES 9 and 10, when there are three conductors 71, three clamps 72 can be spaced apart by three of the combined tie and strut members 73 arranged in the form of a triangle, that is with two of the combined tie and strut members attached to each clamp. Similarly, for a four conductor bundle four clamps 74 can be used with the combined tie and strut members 75 forming a square, two combined tie and strut members projecting from each clamp 74 at right angles to each other.

What we claim as our invention is:

1. A spacer for bundled conductors of overhead lines comprising at least two clamps, each for attachment to a conductor of the bundle, at least one abutment fixed with respect to each clamp, and means for resisting undesirable movements between at least one pair of said clamps comprising a flexible tubular strut in the form of a closecoiled helical spring spacing the clamps of said pair apart, a rectilinear tie member in the form of a flat strip of metal located within the strut and tying the clamps of said pair together, and two supporting structures between which the effective part of the tie member extends each comprising a rigid member attached to the tie member and a flexible member arranged between and so attached to the rigid member and to one of said abutments that the tie member is held substantially in a plane at right angles to the conductor axes of said clamps.

2. A spacer as claimed in claim 1 in which the ends of the tubular strut are secured to the clamps by compression joints.

3. A spacer as claimed in claim 2 in which the flexible member arranged between the rigid member and abutment is a pad of elas-tomeric material.

4. A'spacer as claimed in claim 2 in which the abutments are constituted by the ends of the tubular strut.

5. A spacer as claimed in claim 2 in which the rigid members are metal disks through which the tie member passes and to which it is secured.

6. A spacer as claimed in claim 3 in which the abutments are constituted by the ends of the tubular strut.

7. A spacer for bundled conductors of overhead lines comprising at least two clamps, each for attachment to a conductor of the bundle, and means for resisting undesirable movements between at least one pair of said clamps comprising a flexible tubular strut in the form of a closecoiled helical spring so attached to the clamps of said pair as to hold them apart, a rectilinear tie member in the form of a flat strip of metal located within the strut and tying the clamps of said pair together, and two supporting structures between which the effective part of the tie member extends each comprising a rigid member attached to the tie member and a flexible member which is an extension with spaced turns of said helical spring so attached to the rigid member that the tie member is held substantially in a plane at right angles to the conductor axes of said clamps. l

8. A spacer as claimed in claim 7 in which the rigid members are metal disks through which the tie member passes and to which it is secured.

9. A spacer as claimed in claim 7 in which the ends of the close-coiled part of the helical spring are secured to I the clamps by compression joints.

10. A spacer for at least three bundled conductors of overhead lines comprising at least three clamps, each for attachment to a conductor of the bundle, two abutments fixed with respect to each clamp, and means for resisting undesirable movements between said clamps comprising a number of flexible tubular struts equal to the number of clamps and so interconnecting said clamps as to form a regular polygon, each strut being in the form of a closecoiled helical spring spacing a pair of the clamps, a rectilinear tie member in the form of a flat strip of metal located within each strut and tying the clamps associated with the strut together, and associated with each tie member two supporting structures between which the efiFe-ctive part of the tie member extends, each comprising a rigid member attached to the tie member and a flexible member arranged between and so attached to the rigid member and one of said abutments that the tie member is held substantially in a plane at right angles to the conductor axes of said clamps.

11. A spacer as claimed in claim 10 comprising three clamps and three struts arranged to form a triangle.

12. A spacer as claimed in claim 10 comprising four clamps and four struts arranged to form a square.

13. A spacer as claimed in claim 10 in which the flexible members are open-turn extensions of the close-coiled helical springs and the abutments are the ends of the close-coiled parts of the helical springs.

.14. A spacer as claimed in claim 13 comprising three clamps and three struts arranged to form a triangle.

15. A spacer as claimed in claim 13 comprising four clamps and four struts arranged to form a square.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A SPACER FOR BUNDLED CONDUCTORS OF OVERHEAD LINES COMPRISING AT LEAST TWO CLAMPS, EACH FOR ATTACHMENT TO A CONDUCTOR OF THE BUNDLE, AT LEAST ONE ABUTMENT FIXED WITH RESPECT TO EACH CLAMP, AND MEANS FOR RESISTING UNDESIRABLE MOVEMENTS BETWEEN AT LEAST ONE PAIR OF SAID CLAMPS COMPRISING A FLEXIBLE TUBULAR STRUT IN THE FORM OF A CLOSECOILED HELICAL SPRING SPACING THE CLAMPS OF SAID PAIR APART, A RECTILINEAR TIE MEMBER IN THE FORM OF A FLAT STRIP OF METAL LOCATED WITHIN THE STRUT AND TYING THE CLAMPS OF SAID PAIR TOGETHER, AND TWO SUPPORTING STRUCTURES BETWEEN WHICH THE EFFECTIVE PART OF THE TIE MEMBER EXTENDS EACH COMPRISING A RIGID MEMBER ATTACHED TO THE TIE MEMBER AND A FLEXIBLE MEMBER ARRANGED BETWEEN AND SO ATTACHED TO THE RIGID MEMBER AND TO ONE OF SAID ABUTMENTS THAT THE TIE MEMBER IS HELD SUBSTANTIALLY IN A PLANE AT RIGHT ANGLES TO THE CONDUCTOR AXES OF SAID CLAMPS. 